Corner cutter machine

ABSTRACT

A corner cutting machine particularly adapted for rounding the corners on stacks of paper or the like employing first and second cutting tools, one such tool being slidable with respect to the other such that it slides from the non-operative position with respect to the stack to an operative position upon initiation of the cutting or shaping sequence. Means are provided for locking the movable tool in operative position with respect to the stack during the period when it is actually performing the cutting or shaping operation.

United States Patent BEST AVHLAELE' CG??? 15] 3,656,337 Wark [451 Apr. 18, 1972 [s41 CORNER CUTTER MACHINE 530,780 12/1894 Kingsbury ..83/l6 Inventor: Donald D. Wark, Grand Haven Mich. 1,193,020 8/1916 lrwm ..83/5l7 X [73] Assignee: The Challenge Machinery Company, m f- 1 9 Grand Haven, Mich Attorney-Price, l-leneveld, l-luizenga & Cooper [22] Filed: May 27, 1970 [57] I ABSTRACT [211 App]. No.: 40,893 A comer cutting machine particularly adapted for rounding the comers on stacks of paper or the like employing first and second cutting tools, one such tool being slidable with respect [52] U.S. Cl ..83/374, 83/459, 83/516, to the other Such that it Slides from the nomoperafive position 83/557 83/558 83/563 83/588 83/639 83/640 with respect to the stack to an operative position upon initia- [51] Int. Cl ..B26d 11/00 tion of the cutting or Shaping sequence Means are provided [58] Fleld of Search ..83/374, 459, 516, 517, 557, f locking the movable tool in operative position with respect 83/558, 563, 533, 640 to the stack during the period when it is actually performing the cutting or shaping operation. [56] References Cited 7 7 1 UNITED STATES PATENTS '13 Claims, Drawing Figures 280,996 7/1883 Armstrong 8 3[517X I n2 I I '/ns no n I "'r 'IK Y Qt 105- I y t n-\\\ I us 07 "04 I 1 I to? J1 3 me so 137 I 93 72 92 MIIA S r I i gg? EDI B I 7a u .IZO us at as I21 3%? EVA COPY PATENTEDAPR 18 I972 3,656, 38? sum 1 GF 5 Re my 04 y. 2% alk w W W p .Y B

PATENTEDAPR 18 m2 BEST m mmm v sum 26F 5 FIG. 1

INVENTOR, 00/1/1940 0. wee

A 772 605 Vs BEST AVAILRB E OPY PATENTEDAPRYBIHYZ L C 3,656,887

SHEET 5 BF 5 FIG. 8

mm 3 WW a W0 m l v. 7 M A n 0% z .w W 7 D m mHwuiu in m m CORNER CUTTER MACHINE BACKGROUND OF THE INVENTION This invention relates to cutting apparatus and, more particularly, to such apparatus particularly adapted for shaping the comers of a stack of paper stock.

It has been proposed heretofore to provide an apparatus for rounding the corners on a stack of paper stock such as loose leaf filler wherein the paper is positioned on a suitable support and cutting tools brought into cutting engagement with the opposite corners thereof. It has been proposed, additionally, to mount one of such tools in slidable fashion with respect to the other such that, at the initiation of the cutting sequence, it slides into operative relationship with the stack. This sliding feature functions primarily to permit positioning of the stock within the apparatus with optimum ease. Difficulty has been experienced, however, in maintaining the slidable tool in proper operative position during the cutting sequence and the various structures proposed heretofore for accomplishing this purpose have been quite complicated and expensive.

Similar comments are pertinent with regard to the prior art mode of tool activation, it having been customary in the past to operate both of the tools from a common overhead beam crank actuated from a flywheel-brake arrangement. This mode of activation is, as will be readily appreciated by those skilled in the art, extremely complicated and expensive involving a rather large number of moving parts with consequent maintenance and adjustment problems.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of this invention, therefore, to provide a cutter or shaping mechanism of the type described which is not subject to the disadvantages noted above.

It is an object of this invention, more particularly, to provide such a device employing a movable cutting tool platform wherein the platform and tool will be positively locked into position during the cutting sequence by means of an extremely simple yet virtually fool-proof device.

It is an object of this invention, additionally, to provide an apparatus of the type described embodying separate prime mover means for each of the cutting tools, thus eliminating the complicated mechanical linkages required heretofore and their attendant problems.

It is an object of this invention, additionally, to provide an apparatus of the type described which, because of the individual characteristics and interrelationship of the individual components, can be economically produced and distributed, the apparatus being capable of functioning with a high degree of accuracy and reliability. I

The foregoing as well as other objects of this invention are accomplished by the provision of an apparatus comprising a generally stationary shaping member support means against which one side of the stack to be shaped is positioned. On the opposite side of the stack there is positioned a second shaping member support means which is slidable with respect to the first such means between a first position wherein the stack may be easily inserted between the support means and a second position wherein the shaping member carried thereby is in operative relationship with respect to the stack. Means are provided for locking the slidable member mounting means in operative position during the actual shaping operation. In accordance with a preferred embodiment of this invention, each of the shaping members is driven by a separate prime mover and the noted locking means is energized by the prime mover associated with the movable tool mounting means.

DESCRIPTION OF THE PREFERRED EMBODIMENT This invention will be readily understood by those skilled in the art from a reading of the following specification and an examination of the accompanying drawings in which:

FIG. 1 is a broken, fragmentary, front elevation of the novel apparatus;

FIG. 2 is a broken side elevation thereof;

FIG. 3 is a plan view of the left-hand head assembly;

FIG. 4 is a cross-sectional view taken along the planes IV- IV of FIG. 3;

FIG. 5 is a plan view of the right-hand head assembly;

FIG. 6 is a cross-sectional view taken along the planes Vl VI of FIG. 5;

FIG. 7 is a cross-sectional view taken along the plane Vll- VII of FIG. 5;

FIG. 8 is a cross-sectional view taken along the plane VIII- VIII of FIG. 6;

FIG. 9 is a fragmentary, side-elevational view of the structure shown in FIG. 8; and

FIG. 10 is a schematic illustration of a suitable hydraulic circuit for utilization in the operation of the apparatus of this invention.

Referring initially to FIGS. 1 and 2, the cutting apparatus which is the subject of this invention includes an upstanding cabinet 10 having a back 11, a front 12 and sidewalls 13. Spaced between sidewalls l3 and suitably supported is the work supporting bed or table 14. Positioned rearwardly of table 14 are a pair of spaced, parallel opposed rails 15a and 15b, each such rail including an inwardly extending track and 16b. The rail assemblies 15 are suitably secured and supported within the framework of the apparatus and the horizontal spread therebetween may be adjusted, when necessary, by means of one or more conventional spreaders 17.

Referring now additionally to FIGS. 3 and 4, the left-hand head assembly, indicated generally by the reference numeral 20, includes a mounting plate 21 slidably suspended between the rail tracks 16 and securable thereto at any desired position by means of a clamping bar or bars 22 and suitable cap screws 23. Mounted within plate 21 for sliding, vertical reciprocating movement is the bearing and knife holder assembly 26. This assembly is slidably joumaled through the plate 21 by means of a dovetail mounting bracket 24 having a conventional adjustable gib 25. The mating portion of the bearing and knife holder assembly 26, as is shown clearly in FIG. 3, corresponds generally in size and shape to the bearing portion of the mounting bracket. The connection, thus, provides lateral stability for the assembly as well as vertical reciprocability.

Bearing and knife holder assembly 26 carries a cornering knife 27 retained thereon by suitable adjustable securing screws 28. The veritcally reciprocable assembly 26 includes, additionally, a pressure foot aperture 29 at its upward extremity having suitable bearings 31 forcibly fitted therein. Slidably mounted within the bearings 31 and, thus, through the aperture 29 is the pressure foot guide shaft 30 which carries pressure foot 33 on the lower extremity thereof.

The guide shaft 30 and, thus, the pressure foot 33 are urged resiliently downwardly by means of a coil spring 32 positioned in compressed fashion about shaft 30. Spring 32, as is conven' tional, is compressible such that when the stack of paper is contacted by pressure foot 33 during the cutting stroke of the apparatus, the shaft 30 will slide upwardly within bearings 31 effectively clamping the stack of paper or other stock in the desired cutting position.

Suitably secured by means of cap screws or the like to the lower extremity of the bearing and knife holder assembly 26 is a push arm 35. Threadably secured to push arm 35 at 40 is the knife synchronization and return rod 39 which fonns a component of the return rod assembly 38. The effective length of rod 39 may be altered by rotation of adjustment head 46.

Proceeding upwardly from this threaded interconnection as viewed in FIG. 4, there is next positioned a locking collar 47 and a spacer 41 about rod 39, the rod being slidably mounted through aperture 42 in mounting plate 21. The knife synchronization and return rod functions, inter alia, to bias the mounting plate 21 and the push arm 35 toward one another through the provision of compression springs 43 and 44 compressed between the upper spring retainer 45 and the mounting plate 21. Two such springs are utilized in the preferred embodiment of this invention merely as a means of maintaining the overall diameter of the return rod assembly 38 at a minimum. Should sufficient clearance be available in other embodiments, of course, a single spring of greater force might well be utilized.

The left-hand head assembly 20 is driven by means of a conventional one-way hydraulic cylinder 51 having a casing 52 and a reciprocating'rod 53. The cylinder is pressurized in a manner to be discussed hereinafter through suitable conduits and hoses 54 which are routed to the pump through aperture 55 in mounting plate 21. The casing 52 is secured by any suitable means to mounting plate 21, an aperture 56 being provided in the mounting plate through which a rod 53 passes in reciprocable fashion.

The assembly is provided with a conventional knife shoe 57 adjustably mounted on a suitably protruding portion of plate 21. The shoe has, in the embodiment illustrated, a partially circular cutting edge63 which mates with a similarly shaped knife edge 64 on the downstroke of the apparatus to perform the cutting operation as will be readily appreciated by those skilled in the art.

The left-hand head assembly 20 is provided, finally, with a back gauge 58 and a side gauge 59, both of which are adjustably mounted on plate 21. The forward left-hand corner of the stack of stock is positioned within the apparatus by the operator prior to the cutting cycle such that the forward edge thereof abuts surface 60 on back gauge 58 and the left-hand edge thereof abuts surface 60 on side gauge 59.

The right-hand head assembly 70 is illustrated specifically in FIGS. through 9 and includes a generally U-shaped lock plate 71 slidably positioned beneath the rails 16a and 16b and securable in a given position by means of clamping blocks 72. The left-hand extremities (see FIGS. 8 and 9) of lock plate 71 have upwardly inclined surfaces 73 formed on the underside thereof which locking surfaces, as shown best in FIG. 7, ride in abutment with the rail members 15 and 16.

Slidably suspended between the rail members 16 above lock plate 71 is a slidable mounting plate 75, plate 75 slidingly abutting the rail 16 at 76 (FIG. 7). The slidable mounting plate 75 is biased to the left as viewed in FIG. 6 and out of the paper as viewed in FIG. 7 with respect to lock plate 71 by adjustable force springs 77, such springs bearing against the clamping blocks 72 and the body of locking plate 75. Rotatably or pivotably mounted at 79 within a suitable slot in locking plate 71 is a generally L-shaped lever 78 having an upwardly extending portion 80 which protrudes partially through aperture 83 in sliding plate 75. The lever 78 includes, additionally, a yoke-shaped portion 81 which slidably straddles the right-hand knife synchronization and return rod 119 for a purpose to be described hereinafter.

The lever 78 is provided, finally, with a bearing or contact surface 82 which surface is engaged by collar 121 at the close of the machine upstroke, such engagement rotating lever 78 in clockwise fashion (FIG. 6) about pivot point 79. Such rotation, as will be readily apparent to those skilled in the art, causes plate contacting portion 80 to contact the right-hand edge of aperture 83 in slidable plate 75 forcing the same to the right as viewed in FIG. 6 against the influence of compression springs 77.

The right-hand head assembly 70 is also provided with a lock bar indicated generally by the reference 85. Lock bar 85 has a central aperture 86 therein through which rod 92 of cylinder 90 passes freely in slidable fashion. The extremities of lock bar 85 include inclined wedging or locking surfaces 87 which surfaces, as shown best in FIG. 9, are angled so as to mate in contacting abutment with surfaces 73 on U'shaped lockingplate 71.

The right-hand drive cylinder 90 is similar to that described in connection with the left-hand head assembly and is positioned on the slidable plate 75 in the manner illustrated in FIG. 6. The casing 91 of this cylinder, however, is not secured to sliding plate 75 but, rather, it is secured to locking bar 85 (see FIGS. 7 and 9) by means of suitable bolts 94 which bolts are freely slidable vertically in plate 75.

Cylinder 90 is provided with a rod 92 which passes freely through aperture 93 in plate 75 and aperture 86 in locking bar 85, thereafter coming into abutment with push arm 115. The bolts 94 which interconnect the cylinder casing 91 and the locking bar 85 have a compression spring 96 positioned therearound between sliding plate 75 and locking bar 85. These springs, as will be noted in detail hereinafter, function to prevent premature locking of the right-hand head assembly during a cutting stroke of the apparatus by maintaining the locking bar in non-locking position until a specified amount of force is being exerted by cylinder 90.

The remainder of the components of the right-hand head assembly are quite similar to those discussed previously in connection with the left-hand assembly with the exception that the various moving parts are mounted upon and slidable through slidable mounting plate 75. There is provided on plate 75, thus, a dovetail mounting bracket 104 having an adjustable gib 105. Slidably mounted within the bracket 104 is a bearing and knife holder assembly or column 106 carrying a cornering knife 107 suitably affixed thereto by means of adjustable securing screws 108.

The column or assembly 106 is provided with a pressure foot aperture 109 at its upper extremity through which is slidably mounted by bearings 111 the pressure foot shaft 110. Shaft has a compression spring 112 positioned therearound between the lower extremity of guide aperture 109 and the pressure foot 113. The shaft is retained in its downward position shown by means of a suitable cap 114.

Secured to the lower extremity of the baring and knife holder column 106 is a push arm 115. Push arm 115 extends sidewardly beneath the lock plate 71 and threadably receives at the knife synchronization and return rod 119 of return rod assembly 118.

Adjustably secured to rod 119 immediately above push arm 115 is a collar 82 which functions, as noted previously, to raise and retain lever 78in the position illustrated in FIG. 6 so as to move slidable plate 75 to the right as viewed in that figure. Rod 119 then slidably passes through the yoke members 81 and an aperture 122 in plate 75.

Positioned over rod 119 above plate 75 are inner and outer compression springs 123 and 124 which springs are retained in position by means of an upper spring retainer 125 and a synchronizing adjustment nut 126, the latter nut being operative when rotated to rotate rod 119 within threaded aperture 120 and, thus, alter its effective length.

Sliding plate 75 has adjustably affixed to an inwardly extending portion thereof a conventional knife shoe 137 which, in the embodiment illustrated, is partially circular in configuration. Cutting edge 143 of knife shoe 137 mates with cutting edge 144 of the knife 107 to perform the cutting operation during operation of the apparatus and the relative positions of the two components, of course, are periodically adjusted to insure acceptable cutting of the stock.

The right-hand head assembly includes, additionally, a back gauge 138 and a right-hand gauge 139, surfaces thereof abutting the paper during the cutting operation. The surface 140 on right-hand gauge 139 through abutment with the stack functions to limit the sideways movement of the adjustable plate 75 as will be explained in detail hereinafter.

Referring now additionally to FIG. 10, there is illustrated schematically a suitable hydraulic circuit for use in conjunction with the invention. The fluid supply assembly includes a motor 151 suitably connected to a pump 152 having a relief valve 157. Pump 152 communicates with a hydraulic fluid reservoir 153. Upon actuation of the manual selector valve 158, fluid is routed by pump 152 in suitable supply conduits through the knife-down lock valve 154 and into a flow divider 155. Within flow divider 155, the fluid is divided into equal streams and routed to the left-hand cylinder 51 and the right-hand cylinder 90. Upon deactivation of the manual selector valve 158, the fluid from the cylinders returns to the reservoir.

The cylinders 51 and 90 are activated by the operator by depressing the foot treadle 160, the foot treadle being mechanically interconnected to valve 158. As illustrated in FIG. 1, the valve may be deactivated by means of a depending rod 156 adapted to move up and down with the right-hand assembly. At the completion of the downstroke-Le, when the knives are in contact with the shoes, a suitable striker on rod 156 can be utilized, as will be readily appreciated by those skilled in the art, to mechanically interrupt the linkage between the foot treadle 160 and the valve 158.

The apparatus, conveniently, may be provided with an overhead light' 163 suitably activated from a switch 162 on the forward panel. The motor activation switch 161, conveniently, may be placed adjacent the light switch, suitable operation lights 164 being provided. The motor 151 which runs the hydraulic pump 152, of course, is activated from the switch 151.

OPERATION ing position and connected to a suitable source of power, a

determination is made as to the width of the particular paper to be processed. The spacing between the left-hand head assembly and the right-hand head assembly 70 is then adjusted to a distance exceeding the width of the paper by approximately one-eighth inch by loosening the clamping bars 22 and 72 and sliding the assemblies along the rails 15. Once the proper spacing is achieved, the plates 21 and 71 are firmly clamped to the rails. The heads should be in their raised positions, of course, during execution of this procedure.

The stack of paper to be cut is then placed upon the apparatus with the left-hand edge positioned against the left-side gauge 59 and with the top positioned against the gauges 58 and 138. Such positioning may be easily accomplished since, as noted, the right-hand side gauge 139 clears the right-hand edge of the paper by approximately one-eighth inch at this time.

The spring assembly 77 which bias the slidable plate 75 with respect to the lock plate 71 on the right-hand head assembly should be adjusted in accordance with the weight and thickness of the paper being processed. If a stiff, heavy paper or rather large stack of paper is being processed, adjustment should be made such that the force with which plate 75 is biased leftwardly is rather high while if light or thin stock is being processed this force should be reduced proportionately.

Once proper adjustment has been made, the hydraulic motor 151 is actuated by means of switch 161 and the foot treadle 160 depressed actuating valve 158. Actuation of valve 158 causes hydraulic fluid to flow into the flow divider 153 and then in equal amounts to the cylinders 51 and 90.

Directing attention initially to the left-hand head assembly 20, as pressurized fluid enters cylinder 51, the rod 53 thereof begins to extend pushing push arm and, thus, return spring shaft 39 and column 26 downwardly. This downward movement is resisted, of course, by the compressing springs 43 and 44 but the hydraulic force is sufficiently great to overcome these springs as well, of course, as to make the desired cut in the stock.

As the column 26 lowers, the pressure foot 33 contacts the paper. Such contact is effected slightly before contact by knife head 64 and, as the stroke is continued, the rod 30 moves upwardly within aperture 29 against the bias of the compression spring 32. Such action effectively clamps the paper in the position in which it was originally placed and the corners of the stock are rounded in accordance with the configuration of the knife 27 and shoe 57, the downward stroke being continued until such time as the knife has come into slicing engagement with the shoe 57 and, thus, the entire stack of paper has been cut.

At the bottom" of the stoke, the hydraulic pressure is released and the assembly is forced upwardly to its original position by compression springs 43 and 44 moving the return rod assembly upwardly. Lateral stabilization of the assembly is assured during the entire operation by suitable adjustment of the gib 25 in the dovetail mounting plate 24.

Operation of the right-hand head assembly during the cutting and return stroke is somewhat more complicated and will now be described. Upon depression of the foot treadle (simultaneously and in synchronization with the operation of the left-hand head assembly as just described) the hydraulic cylinder receives pressurized fluid and its rod 92 commences a downward stroke. The rod 92, as discussed previously, abuts push arm and, thus, commences immediately to move return rod 119 and knife support column 106 downwardly.

As return rod 119 commences this downward movement, the support collar 82 for lever 78 moves downwardly also, permitting lever 78 to rotate in counterclockwise fashion as viewed in FIG. 6 in response to the pressure from springs 77. This rotation, in turn, permits sliding plate 75 carrying the cylinder 90, knife column 106 and return rod assembly 118 to move leftwardly (also under the influence of spring assemblies 77) until such time as the surface of right-hand gauge 139 slides into abutment with the right-hand side of the stack.

The hydraulic cylinder housing 91, as noted previously, is not connected directly to sliding plate 75 but, rather, is connected to locking bar 85. As the downward stroke of the righthand head assembly is continued, thus, the pressure foot 113 comes into contact with the stack of paper clamping it into position for cutting. This foot, in exactly the same manner as described in connection with the left-hand head assembly, retracts upwardly with respect to the column 106 through compression of the spring 112 during the remainder of the downstroke cycle.

The compressing of the spring 112 as well, of course, as the cutting of the paper by the knife 107 causes the expanding cylinder 90 to encounter increased resistence and, since the cylinder casing 91 is not affixed to the sliding plate 75, it tends to move upwardly with respect thereto. Such movement ispermitted insofar as allowed by the effective length of attaching screws 94 (see FIG. 7) and the upward force of casing 91 is thereafter translated into an upward force on locking bar 85. This upward force on locking bar 85 causes the inclined surface 87 of the locking bar to tightly abut the inclined surface 73 of the lock plate 71. The contact of these four surfaces effectively secures or locks the lateral or sideways position of the sliding plate 75 with respect to the locking plate 71 resisting any tendency for the sliding plate 75 to slide to the right during the cutting stroke and, thus, insuring a proper vertically oriented cut.

The cylinder 90 must overcome from inception of the downward cutting stroke, of course, the force of return compression springs 123 and 124. The force required for this purpose may, in many instances, be sufficient to cause the cylinder 90 to move upwardly with respect to sliding plate 75 prematurely and, thus, cause the locking bar 85 to lock the sliding plate 75 with respect to locking plate 71 prior to the time that lever 78 has toggled a sufficient amount to permit the right-hand head assembly to assume its proper position for the cutting stroke under the influence of spring assembly 77. Such premature locking can be effectively overcome by the utilization of compression springs 96 (FIG. 7) around the bolts 94 between the sliding plate 75 and the locking bar 85. These springs function, as will be readily apparent to those skilled in the art, to maintain the spacing between the locking bar 85 and the sliding plate 75 at the optimum distance permitted by the effective length of bolts 94 until such time as the cylinder is encountering sufficient resistence to compress the spring 96. If the bolts 94 are backed off approximately one-quarter of a turn from the tight position during initial adjustment of the machine, no effective upward locking thrust on the locking bar 85 will be encountered until such time as the lever 78 has had sufficient time to pivot and, thus, the sliding plate 75 sufficient time to move into gauge abutment with the stack of paper.

As the pressure foot 113 and knife 107 encounter resistence from the stack of paper, thus, the compression of springs 96 is overcome and the knife column 106 locked into position by the upward force of cylinder casing 91 with respect to plate 75. This locking action is maintained until such time as the downward cut has been completed and the pressure released from cylinder 90. The assembly is then returned to its initial upward position shown in FIG. 6 under the influence of the return springs 123 and 124. As the return stroke is initiated, the locking engagement between surfaces 73 and 87 is released because of the relaxation of cylinder thrust and the sliding plate 75 is held in position against the paper only because of the force of the lateral spring assemblies 77.

As the return rod moves upwardly, collar 121 eventually contacts surface 82 of lever 78 rotating it clockwise as viewed in FIG. 6. Such rotation causes surface 80 to abut the righthand edge of aperture 83 in sliding plate 75 and move the plate along with the knife column, etc., to the right against the influence of the spring assemblies 77. Once the return stroke has been completed, the sliding plate 75 will have returned to the initial position illustrated in FIG. 6, the right-hand gauge 139 will be approximately one-eighth of an inch away from the side of the paper and the stack with the rounded comers may thereafter be removed and a new stack inserted.

During sliding movement of the sliding plate 75 into abutment with the paper at the initiation of the cutting stroke, of course, the locking bar 85 must slide laterally with respect to locking surfaces 73 on lock plate 71. As a means of permitting such sliding movement, the lateral measurement of locking surfaces 73 exceeds the lateral measurement of surfaces 87 on lock bar 85. The mating angles permit, however, effective locking of the assemblies regardless of the exact lateral position of the locking bar 85 with respect to the locking plate 71.

The instant invention contemplates, as noted previously, the simultaneous and synchronized movement of each of the knife columns into mating positions with the knife shoes 57 and 137. Such movement is effected primarily by the hydraulic flow divider 155. Initial synchronization is obtained by rotating the knife synchronization and return rods 39 and 119 to adjust the length of stroke necessary to bring the knives into mating engagement with the shoes. Such rotation, as will be readily appreciated by those skilled in the art, effectively alters the spacing between the push arms 35 and/or 115 and their respective support assemblies through the threaded unions 140 and 120 between the return rods and the push arms. Vertical stability of the rod is maintained because of the presence of the locking collars 47 and 82.

Such rotation of the return and synchronization rods 39 and 119 may be utilized, additionally, to shorten or lengthen the effective stroke of the apparatus where such is desired to accommodate differing heights of stacks. Such an adjustment, as will be readily evident, can shorten dramatically the time period required for a particular cycle and, thus, result in a commensurate increase in production. To this end, the lower threaded portions of the rods 39 and 119 preferably extend below the push arms 35 and 115 in the positions shown in FIGS. 4 and 6 a suitable distance to permit such adjustment.

A convenient method of deactivating the flow of hydraulic fluid to the cylinders at the completion of the down or cutting stroke can be effected through the utilization of an elongated rod assembly 156 (see FIG. 1) affixed for vertical movement with the right-hand head assembly 70. The rod, for example, may be affixed to push arm 115. Through suitable adjustment of the effective length of this rod, it may be made to contact a trip or, preferably, cause an interruption in the mechanical interconnection of the foot treadle and the valve 158 when the knife 107 has come into mating engagement with the shoe 137. This adjustment should be accomplished, of course, prior to synchronization of the knives by the rotation of the synchronizing rods 39 and 119.

The knife down lock valve 154 may be utilized during adjustment of the knives and shoes to retain the knives in their downward position. This valve functions, as will be noted clearly from an examination of FIG. 10, to lock the return flow of fluid from the cylinders 51 and 90 and, thus, maintain the rods 92 and 53 in their extended positions. Once proper knife and shoe adjustment has been effected, the valve may be reopened to permit the knife assemblies to return to their starting or upward position dictated, as noted, by the axial adjustment of the synchronization rods 39 and 119.

The concepts of the instant invention are not limited, of course, to a comer-rounding operation. The knives and shoes, in fact, may take any desired configuration. Nor is the description of the preferred embodiment of this invention to be taken as in any manner limiting the scope thereof since, as will be readily apparent in the art, numerous other embodiments may be conceived and fabricated without departing from the teachings of the specification. Such other embodiments, rather, are to be deemed as included as within the scope of the following claims unless these claims, by their language, expressly state otherwise.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

1. In an apparatus for performing a shaping operation on a stack of paper or the like having a pair of spaced shaping members between which said stack is placed, said shaping members, upon actuation thereof being adapted to contact and shape said stock, at least one of said members being adaptable after such placement to move toward the other such member such that the stack is engaged from both sides to accurately position said shaping members with respect thereto, the improvement comprising means for locking said one shaping member in position after it has moved into engagement with said stack, said locking means being automatically responsive to actuation of said shaping members.

2. The apparatus as set forth in claim 1 wherein the other of said members is stationary during said shaping operation, each of said members including gauges adapted to abut the sides of said stack during contact thereof by said shaping members.

3. The apparatus as set forth in claim 2 wherein said shaping members reciprocate vertically to perform said shaping operation.

4. The apparatus as set forth in claim 1 which further comprises means for inhibiting activation of said locking means for the initial portion of said shaping operation.

5. The apparatus as set forth in claim 1 wherein said locking means includes locking plate means secured in fixed position on said apparatus, sliding plate means slidable with respect to said locking plate means and locking bar means movable with said sliding plate means, said shaping member being positioned upon said sliding plate means, said locking bar means being movable into locking engagement with said locking plate during said shaping operation.

6. The apparatus as set forth in claim 5 wherein said shaping members reciprocate vertically to perform said shaping operation and which further comprises a hydraulic cylinder associated with said one member adapted to reciprocate it, the casing of said cylinder being secured to said locking member.

7. The apparatus as set forth in claim 6 wherein said one shaping member comprises a knife supporting column movable vertically with respect to said sliding plate means, the piston rod of said cylinder extending slideably through said sliding plate means and said locking bar means and being operatively connected to said column for moving the same.

8. The apparatus as set forth in claim 7 which further comprises spring means biasing said column upwardly.

9. The apparatus as set forth in claim 8 which further comprises means for inhibiting activation of said locking means for the initial portion of said shaping operation.

10. The apparatus as set forth in claim 5 wherein said one shaping member comprises a knife supporting column movable vertically with respect to said sliding plate means and slidable therewith and which further comprises means for controlling the position of said sliding plate means with respect to said locking plate means in response to the vertical position of said column.

11. The apparatus as set forth in claim 10 wherein said controlling means comprises a lever means pivoted on said locking plate means, a portion of said lever means contacting said sliding plate means so as to move the same with respect to said locking means when said lever means is pivoted.

12. The apparatus as set forth in claim 11 which further comprises means movably vertically with said knife column for pivoting said lever means to move said sliding plate means 

1. In an apparatus for performing a shaping operation on a stack of paper or the like having a pair of spaced shaping members between which said stack is placed, said shaping members, upon actuation thereof being adapted to contact and shape said stock, at least one of said members being adaptable after such placement to move toward the other such member such that the stack is engaged from both sides to accurately position said shaping members with respect thereto, the improvement comprising means for locking said one shaping member in position after it has moved into engagement with said stack, said locking means being automatically responsive to actuation of said shaping members.
 2. The apparatus as set forth in claim 1 whereiN the other of said members is stationary during said shaping operation, each of said members including gauges adapted to abut the sides of said stack during contact thereof by said shaping members.
 3. The apparatus as set forth in claim 2 wherein said shaping members reciprocate vertically to perform said shaping operation.
 4. The apparatus as set forth in claim 1 which further comprises means for inhibiting activation of said locking means for the initial portion of said shaping operation.
 5. The apparatus as set forth in claim 1 wherein said locking means includes locking plate means secured in fixed position on said apparatus, sliding plate means slidable with respect to said locking plate means and locking bar means movable with said sliding plate means, said shaping member being positioned upon said sliding plate means, said locking bar means being movable into locking engagement with said locking plate during said shaping operation.
 6. The apparatus as set forth in claim 5 wherein said shaping members reciprocate vertically to perform said shaping operation and which further comprises a hydraulic cylinder associated with said one member adapted to reciprocate it, the casing of said cylinder being secured to said locking member.
 7. The apparatus as set forth in claim 6 wherein said one shaping member comprises a knife supporting column movable vertically with respect to said sliding plate means, the piston rod of said cylinder extending slideably through said sliding plate means and said locking bar means and being operatively connected to said column for moving the same.
 8. The apparatus as set forth in claim 7 which further comprises spring means biasing said column upwardly.
 9. The apparatus as set forth in claim 8 which further comprises means for inhibiting activation of said locking means for the initial portion of said shaping operation.
 10. The apparatus as set forth in claim 5 wherein said one shaping member comprises a knife supporting column movable vertically with respect to said sliding plate means and slidable therewith and which further comprises means for controlling the position of said sliding plate means with respect to said locking plate means in response to the vertical position of said column.
 11. The apparatus as set forth in claim 10 wherein said controlling means comprises a lever means pivoted on said locking plate means, a portion of said lever means contacting said sliding plate means so as to move the same with respect to said locking means when said lever means is pivoted.
 12. The apparatus as set forth in claim 11 which further comprises means movably vertically with said knife column for pivoting said lever means to move said sliding plate means out of engagement with said stack when said column is in its upward position.
 13. The apparatus as set forth in claim 12 wherein said pivoting means comprises a return rod biased upwardly with respect to said sliding plate means and slidable therewith, said return rod being fixed for vertical movement with said column and having a portion thereon adapted to engage and pivot said lever when said column is in its upward position. 